By contrast, while it's clear that some CEOs are excellent leaders and managers, there's little evidence that individual executives are blessed with consistently good strategic foresight. In fact, in an extensive study of intelligent CEOs who made disastrous decisions, Dartmouth's Sydney Finkelstein writes, "CEOs should come with the same disclaimer as mutual funds: Past success is no guarantee of future success." Even when executives are smart, they have a hard time getting the information they need - at so many firms the flow of information is shaped by political infighting, sycophancy, and a confusion of status with knowledge. Hierarchies have certain virtues - efficiency and speed - as a way of executing decisions. But they're outmoded as a way of making decisions, and they're ill-suited to the complex strategic landscapes that most companies now inhabit. Firms need to aggregate the collective wisdom instead.